A power tool known as an impact tool (e.g., an impact driver or an impact wrench) generally includes a motor, a transmission, an impact mechanism, and an output shaft. The impact mechanism generally includes a cam shaft coupled to the transmission, a hammer received over the cam shaft for rotational and axial movement relative to the cam shaft, an anvil coupled to the output shaft, and a spring that biases the hammer toward the spindle. When a low amount of torque is applied to the output shaft, the hammer remains engaged with the anvil and transmits rotational motion from the transmission to the output shaft without any impacts. When a higher amount of torque is applied to the output shaft, the hammer disengages from the anvil and transmits rotary impacts to the anvil and the output shaft. The mechanical characteristics of the impact mechanism components generally determine the output torque at which the impact mechanism transitions from operation in the rotary mode to the impact mode (referred to herein as the normal transition torque).